Self-aligning return roller for belt conveyers



Dec. 15, 1942 R. H. SALFISBERG SELF ALIGNING RETURN ROLLER FOR BELTCONVEYER Filed April 18, 1941 2 Sheets-Sheet 1 ATTORNEYS.

Dec. 15, 1942. R.-H. SALFISBERG SELF ALIGNING RETURN ROLLER FOR BELTCONVEYI EZR 2 Sheets-Sheet 2 I Filed April 18, 1941 Patented Dec. 15,1942 UNITED STATES SELF-ALIGNING RETURN ROLLER FOR BEIJT CONVEYERSRobert H. Salfisberg, Aurora, 111.,

assignor to Application April .18, 1941, Serial No. 389,110

3 Claims.

This invention relates to belt conveyers and particularly to rollerswhich support the return run of the belt. Commonly the return rollers,as they are called, are cylindrical pulleys mounted on straight shaftsand have no inherent training action to correct the usual tendency ofthe return run of the belt to creep to one side or the other.

The principal object of this invention is to make travel of the belt toone side react through the roller to produce a training effect on thebelt. Generally speaking, this is accomplished by mounting the returnroller to swing about an axis in a vertical plane through the normalcenter line of the belt and preferably inclined in the direction of thereturn run of the belt. With such an arrangement the excess weight ofthe belt traveling to one side of the normal center line will tend toswing the corresponding end of the return roller forwardly and theopposite end backwardly, thus setting the roller askew in position totrain the belt towards its normal position. If the axis of the swingingmovement for the roller is inclined forwardly, as is preferable, the endof the roller that is moved forward by the weight of the belt will alsoswing downward while the opposite end will swing upwardly as well asbackwardly, and the roller as a whole will thus be inclined and skewedin a manner to train the belt to normal central position. As the beltapproaches that position the relative weight on the opposite endportions of the roller will approach equality and the training tendencywill diminish until it disappears with the return of the belt to itsproper traveling position.

In practical use of such return rollers any movement of the belt to oneside at once sets the roller for a corresponding training action toreturn the belt and in consequence the belt hardly deviates noticeablyfrom its right line of travel on the return run.

Further objects and advantages of the invention will appear as thedescription is read in connection with the accompanying drawings, inwhich Fig. 1 is a diagrammatic side elevation of a belt conveyer;

Fig. 2 is a fragmentary side elevation showing a return rollerarrangement beneath a fragment of the main conveyer frame;

Fig. 3 is a transverse section through the return run of the belt and alongitudinal section through a return roller arrangement;

Fig. 4 is a plan view looking down from the line 4-4 in Fig. 4.;

Fig. 5 is a longitudinal section through the central supporting bracketof the return roller mounting;

Fig. 6 is a similar section showing a modified form of support for thereturn roller;

Fig. 7 is a plan view of the same, and

Figs. 8 and 9 are diagrammatic illustrations of other forms.

In the diagram shown in Fig. l a belt conveyer i0 is trained about ahead pulley II and a tail pulley i2 with the load carrying run of thebelt supported on the rollers l3 and the return run on the rollers I4.

The preferred mounting for the return rollers is shown in detail inFigs. 2 to 5. It includes two generally V-shaped brackets l5, hangingdown from the girders iii of the main conveyer frame, to which they aresecured by bolts ll. Each bracket has hollow bosses l8, which receivethe corresponding ends of tubular beams I9, secured in place by setscrews 20. The beams l9 span the conveyer frame work and about the'middle are equipped with a central supporting bracket 2!, having bossesbeams l9 and are secured The bracket 2| includes spaced jaws 24 and 25,having adjacent faces machined and threaded in alignment to receivetrunnions 28 and 21 arranged on an axis lying in a vertical planethrough the normal center line of the conveyer belt I0. The trunnions 26and 21 are received in bushed bearings 28 in the enlarged middle portion29 (Fig. 3) of a hollow shaft bearing member or casing 30.

The end portions 3| of the casing 30 are enlarged to receive ballbearings 32 for the return roller shaft 33. This shaft extends throughthe bearings to which it is secured by set screws 34 and has projectingend portions 35 upon each of which is mounted a pulley 36 including arim portion 31, web portions 38 and hub portions 39, the latter securedto the shaft by set screws 40. A suitable thrust bearing 4| is insertedbetween the jaw 25 and the corresponding face of the enlarged portion 29on sleeve 30.

The return run of the belt aligned rim portions 3! of the two pulleys 36which together serve as a return roller, their adjacent edges beingseparated slightly as shown in Fig. 3 to make room for the centerbracket 2|.

In operation, any displacement of the belt to one side will make adifferential of weight in favor of that side which will result in atendency to swing the corresponding pulley 36 forwardly and downwardly,the whole roller assembly rotating about 22, which fit over the by setscrews 23.

I0 rests on the the trunnions 26. The unavoidable reaction is to swingthe opposite pulley 31 upwardly and rearwardly, thus the roller formedby the two pulleys 36 is skewed and inclined upwardly towards thelighter side of the belt and both the skewing and the inclination tendto train the belt towards that side. As the belt approaches its normalcentral position the weight difierential is reduced and therefore thetendency to skewing and training is reduced as it finally disappearsuntil the belt comes back to normal position. From this it will be seenthat in practical operation a tendency to' creep to one side isimmediately opposed bya tendency to train the belt back to properposition and, in consequence, there is hardly'any noticeable departurefrom the normal central path of the return run. The sleeve or casing 30is provided with limit stop arms 42 (Figs. 3 and 4) to cooperate withsurfaces 33 on the bracket 2| to limit the pivotal movement about thetrunnions 26 to the range indicated by the dotted lines in Fig. 4.

In Figs. 6 and '7 there is illustrated a modified construction in whichthe. axis of swinging. movement for the return roller is removed fromthe axis of the roller. A central bracket Min this arrangement replacesthe bracket 2| and is. fitted with an upright trunnion 45 on whichabearing arm 46 of a sleeve or casing ll is journaled by suitableanti-friction bearings 48. The sleeve has enlargements 49 (Fig. 7)corresponding to enlargements 3! in which the anti-friction bearingsfor. the shaft 33 are received.

In use this construction follows the general operation described inconnection with the preferred form except that there is no tiltingofthe. return roller. The anti-friction bearings 48 are. used to make themovementsensitive to slight differences in weight. and friction onopposite. sides of the return run.

For those who desire tilting in thissort of .struc-' ture alternativearrangements shownjnFigs- 8. and 9 may be used. In each of these acentralf bracket carried by the beams I9, is. equipped with a trunnion52 for a bearing arm 53, corre: sponding to the arm 46 in Fig.6,,andafiording'a similar support for the pulleys 36.

In each of these forms shown in Figs. 8 and 9,. however, the trunnion isinclined at an, angl of. 30 to the Vertical correSpOnding. withthe.form. shown in Figs. 2 to 5. In Fig. 8 the trunnion, and! therefore theaxis of the swinging movement, is. back of the returnroller,,whereas.in.Fig..9 it is infront of the return roller, backandfrontbeing:

considered with respect to the return run. ofzthe belt. In the threeformsv showninv Figs. 6,..7, 8 and 9, limits to the swinging movementmaytbaset. by limit stop arms 54 on the bracket and an.arm-i 55 on thebearing arm. With the axis of swing at 30 to the vertical, the fore andaft movement of the return roller with respect to the belt is twice theup and down motion and this enhances the tendency to corrective action.

In order to lubricate the roller bearings 32 for the shaft 33, theenlarged middle portion of the casing 30 is fitted with a suitablegrease nipple 56, by which the casing may be charged with grease.

The forms here shown and described are merely illustrative and manyothers will be readily designed to suit personal preference orparticular conditions. The framework of the conveyer has beenassumed asconventional and the supporting brackets l5 and tubular beams R9 aremerely one selection of those elements from many available.

I claim:

I. In a self training return roller for belt conveyers, a supportingbracket, a casing, cooperating pivot means on said casingand bracket forpivotally connecting. said casing to said bracket toswing. to and from ahorizontalposition-crosswise to the return run of the belt, .a shaftextendingv axially through the casing, bearings between said shaft andcasing at the ends of said casing, and a'pulley carried by the shaftateach. side of the axis about which the casing swings, each of saidpulleys being outwardly of said pivot means but in proximity thereto.

2. In a self-training roller for belt conveyers, a supporting bracketbifurcated at its upper end, a. bearing casing between the furcationsand pivoted thereto to swing aboutaninclined axis, a shaft extendingaxially through said bearing cas ing. and journaled thereinat-each endof the cas-- ing, a pair of pulleys surrounding said shaft and bearingcasing and supported by said shaft, said pulleys having their inner endsspaced apart a sufficient distance to clearisaid bracket, the axis of.the pivot extending'upwardlyand vfor-wardlyinthe. direction. of travel.ofthe lower: run of -th'e belt conveyer.

3. In a belt conveyer, a conveyer frame,brackets secured toand dependingfrom saidframe at the sides thereof, a pair of beamssupported by saidbrackets and extending transverselyto theaxis' of said conveyer; asupporting bracket sli'dably mounted on said beams.andadjustabl'e alongthe same, said: supporting. bracket having jaws spaced apart,alignedtrunnionstcarried by said jaws, a

casingjournaledon said trunnion's-to swing about an: inclined axis, .ashaft extendingthrough said; casingand journaled thereimand-a pulleyremov '-ably mounted on eachendof said -shaft;--saidpulleys being spacedjust sufficient to 7. provide clearancefor said supporting bracketsROBERTl-I. SAIFISBERG.

